You can play music tracks through Dropbox's web interface, but only one at a time, in a very minimalist player. DropTunes provides a great web front-end for your Dropbox-synced tunes, offering Flash or HTML5-based streaming and continual playback. It's pretty darned handy.

You'll need to log into Dropbox through DropTunes to fire it up, of course, but you don't need Dropbox installed on a machine to use DropTunes. Launch the site, then pick out your folder with your music stash in the left-hand folder list. If you're syncing your iTunes library with Dropbox, DropTunes could be your personal Cloud Drive, and it's an easy way to share tunes with fellow Dropbox users—share the folder, and they can instantly access it through DropTunes. When the developer gets around to adding keyboard shortcuts, it's a safe bet we'll have a hard time containing our hyperbole.

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DropTunes is a free service that requires a Dropbox account to use. It supports Flash-free HTML5 playback, but doesn't specifically support iOS or Android devices—though you may have some luck in the browser.